The heartbroken widow of shoe magnate Mike Silverstein claims his business partner brother coldly reneged on a $1 million family pact to protect their spouses if one of them died, according to court filings.

Renee Silverstein, 77, filed a federal lawsuit this week against Stanley Silverstein, 87, who co-founded famed Nina Shoes with her husband in 1953 and grew it from a single SoHo store into an international retail juggernaut.

The Port Washington widow claims that Silverstein has brazenly ignored a 2007 agreement with his brother that entitled the wife of whichever sibling died first to 30 months of his company salary to protect their finances, according to the suit.

Silverstein passed away in March.

“Mike would obviously be devastated if he knew that you are deliberately refusing to honor your agreement with him and with me,” she wrote in an e-mail to her brother-in-law, according to the suit. “I have to believe that you plan to make the honorable choice as the alternative and all that entails is too heartbreakingly painful to even contemplate.”

In the suit, the widow claims that the brothers were in the process of negotiating a sale to Stanley Silverstein’s powerful son-in-law, A Children’s Place founder and Nina CEO Ezra Dabah, when Mike Silverstein died.

Renee Silverstein made it clear to both Stanley Silverstein and Dabah that she expected to be paid her husband’s monthly salary of $34,480,083 for the next 30 months for a total of more than $1 million, according to the suit.

But the dashing Dabah refused to approve the Nina Shoes sale if the death benefit to Renee Silverstein was included in the deal. He even threatened to resign from the company completely if his demands weren’t met, the suit states.

The widow claims that Dabah and his father-in-law tried to strong-arm her into relinquishing the death benefit by threatening to declare bankruptcy. But after inheriting half of the company’s voting shares upon her husband’s death, Renee Silverstein was able to block them at every turn, according to the lawsuit.

Anxious to make the sale to his son-in-law, Stanley Silverstein finally convinced the widow to sign off on the deal by promising to make the payments to her himself. After drafting a contract to that end, the sale closed and Dabah owned Nina.

That purchase immediately placed Dabah on a list of the 100 most powerful people in the shoe business, according to Footwear News.

But the angry widow claims that Stanley Silverstein has all but vanished after the deal closed and that she hasn’t been paid.

“Nonetheless, since that closing, Stanley Silverstein has failed to pay Renee Silverstein a single dollar of death benefit payments he agreed to pay her,” the suit states.

Renee Silverstein launched the suit this week only after her anguished pleas to her estranged in law were ignored completely, the suit states.

Nina officials and Stanley Silverstein would not comment on the case. Renee Silverstein also declined to comment.